Yuto Kimura

Inhibitory role of Gas6 in intestinal tumorigenesis

Growth arrest-specific gene (Gas) 6 is a γ-carboxyglutamic acid domain-containing protein, which shares 43% amino acid identity with protein S. Gas6 has been shown to enhance cancer cell proliferation in vitro. On the other hand, recent studies have demonstrated that Gas6 inhibits toll-like receptor-mediated immune reactions. Immune reactions are known to affect intestinal tumorigenesis. In this study, we investigated how Gas6 contributes to tumorigenesis in the intestine. Administration of recombinant Gas6 weakly, but significantly, enhanced proliferation of intestinal cancer cells (SW480 and HT29), whereas it suppressed the inflammatory responses of Lipopolysaccharide (LPS)-stimulated monocytes (THP-1). Compared with Gas6(+/+) mice, Gas6(-/-) mice exhibited enhanced azoxymethane/dextran sulfate sodium (DSS)-induced tumorigenesis and had a shorter survival. Gas6(-/-) mice also exhibited more severe DSS-induced colitis. DSS-treated Gas6(-/-) mice showed attenuated Socs1/3 messenger RNA expression and enhanced nuclear factor-kappaB activation in the colonic stroma, suggesting that the target of Gas6 is stromal cells. Bone marrow transplantation experiments indicated that both epithelial cells and bone marrow-derived cells are Gas6 sources. Furthermore, the number of intestinal tumors in Apc(Min) Gas6(-/-) mice was higher than that in Apc(Min) Gas6(+/+) mice, resulting in shorter survival. In a group of 62 patients with advanced colorectal cancer, Gas6 immunoreactivity in cancer tissues was positively correlated with prognosis. Thus, we revealed a unique in vivo inhibitory role of Gas6 during the progression of intestinal tumors associated with suppression of stromal immune reactions. These results suggest a novel therapeutic approach for colorectal cancer patients by regulation of stromal immune responses.

Deletion of nardilysin prevents the development of steatohepatitis and liver fibrotic changes

Nonalcoholic steatohepatitis (NASH) is an inflammatory form of nonalcoholic fatty liver disease that progresses to liver cirrhosis. It is still unknown how only limited patients with fatty liver develop NASH. Tumor necrosis factor (TNF)-α is one of the key molecules in initiating the vicious circle of inflammations. Nardilysin (N-arginine dibasic convertase; Nrd1), a zinc metalloendopeptidase of the M16 family, enhances ectodomain shedding of TNF-α, resulting in the activation of inflammatory responses. In this study, we aimed to examine the role of Nrd1 in the development of NASH. Nrd1+/+ and Nrd1−/− mice were fed a control choline-supplemented amino acid-defined (CSAA) diet or a choline-deficient amino acid-defined (CDAA) diet. Fatty deposits were accumulated in the livers of both Nrd1+/+ and Nrd1−/− mice by the administration of the CSAA or CDAA diets, although the amount of liver triglyceride in Nrd1−/− mice was lower than that in Nrd1+/+ mice. Serum alanine aminotransferase levels were increased in Nrd1+/+ mice but not in Nrd1−/− mice fed the CDAA diet. mRNA expression of inflammatory cytokines were decreased in Nrd1−/− mice than in Nrd1+/+ mice fed the CDAA diet. While TNF-α protein was detected in both Nrd1+/+ and Nrd1−/− mouse livers fed the CDAA diet, secretion of TNF-α in Nrd1−/− mice was significantly less than that in Nrd1+/+ mice, indicating the decreased TNF-α shedding in Nrd1−/− mouse liver. Notably, fibrotic changes of the liver, accompanied by the increase of fibrogenic markers, were observed in Nrd1+/+ mice but not in Nrd1−/− mice fed the CDAA diet. Similar to the CDAA diet, fibrotic changes were not observed in Nrd1−/− mice fed a high-fat diet. Thus, deletion of nardilysin prevents the development of diet-induced steatohepatitis and liver fibrogenesis. Nardilysin could be an attractive target for anti-inflammatory therapy against NASH.

Acute Pancreatitis as a Possible Indicator of Pancreatic Cancer: The Importance of Mass Detection

OBJECTIVE The aims of this study were to assess the incidence of pancreatic cancer and the contributing factors for the diagnosis of tumors in patients with acute pancreatitis and to gain insight into how patients with acute pancreatitis should be followed up. METHODS Using the electronic medical database of Shizuoka General Hospital, 177 patients admitted for acute pancreatitis in the past 6 years were evaluated retrospectively for pancreatic cancer. RESULTS Twelve patients (6.8%) were newly diagnosed with pancreatic cancer. During the first hospitalization, 5 patients (41.7%) with a detected pancreatic mass underwent surgical treatment: the final tumor stages were IA, IIA, and IIB in 1, 2, and 2 patients, respectively. In 7 patients (58.3%) without a detected pancreatic mass at the first admission, a pancreatic mass was recognized on follow-up computed tomography (CT) in 2 patients with main pancreatic duct (MPD) dilatation, and 1 patient with recurrent acute pancreatitis. The tumor stages were IA, IIA, and IA, respectively. Among the remaining 4 patients without follow-up, the tumor stage was IV. The patient gender, age, MPD dilatation, tumor marker, and serum amylase level were not significantly associated with pancreatic cancer. The detection of a pancreatic mass on CT led to the diagnosis of pancreatic cancer. CONCLUSION Acute pancreatitis should be considered as a possible diagnostic indicator of pancreatic cancer. Various factors associated with acute pancreatitis and pancreatic cancer were not predictive of a diagnosis of pancreatic cancer. Only the detection of a pancreatic mass led to the early diagnosis of pancreatic cancer. Patients hospitalized for acute pancreatitis should be followed up with a diagnostic imaging modality.

Nardilysin regulates inflammation, metaplasia, and tumors in murine stomach

Chronic inflammation contributes to a wide variety of human disorders. In the stomach, longstanding gastritis often results in structural alterations in the gastric mucosa, including metaplastic changes and gastric cancers. Therefore, it is important to elucidate factors that are involved in gastric inflammation. Nardilysin (N-arginine dibasic convertase; Nrdc) is a metalloendopeptidase of the M16 family that promotes ectodomain shedding of the precursor forms of various growth factors and cytokines by enhancing the protease activities of a disintegrin and metalloproteinase (ADAM) proteins. Here, we have demonstrated that Nrdc crucially regulates gastric inflammation caused by Helicobacter felis infection or forced expression of prostaglandin E2 in K19-C2mE mice. Metaplastic changes following gastric inflammation were suppressed by the deletion of Nrdc. Furthremore, the deletion of Nrdc significantly suppressed N-methyl-N-nitrosourea (MNU)-induced gastric tumorigenesis in the murine stomach. These data may lead to a global therapeutic approach against various gastric disorders by targeting Nrdc.

Virtual Enteroscopic Images of Meckel's Diverticulum

V enteroscopy (VE) is a newly developed method to explore the entire small intestine with a modified protocol f virtual colonoscopy by inflating the small intestine with air hrough a jejunum-intubated tube and depicting the wall of the mall intestine. A 66-year-old man presented to our hospital with progressive nemia and a positive fecal occult blood test. He had undergone emodialysis for 15 years for renal failure caused by chronic lomerulonephritis. Erythropoietin and nonsteroidal anti-inammatory drugs (NSAIDs) had been given regularly for renal nemia and chronic thoracic pain. Esophagogastroduodenosopy and colonoscopy were performed, but the source of bleedng could not be identified. Video capsule endoscopy (VCE) was erformed, and multiple small erosions in the small bowel were ound. VE was performed, revealing the total length of the small owel was 595 cm (Figure A, B). At 103 cm from the ileocecal alve (Figure B, white arrow), an 8-cm–long diverticulum was depicted (Figure C, luminal view; Figure D, 3-dimensional overview; Figure E, wall view; black arrow, lumen of the intestine; white arrow, opening of the diverticulum; Supplementary Video 1), which could not be identified in a second look of the results of VCE. Meckel scan results were negative. Erosions found by VCE were not depicted by VE. Considering the location, size, and shape, a diagnosis of Meckel’s diverticulum was made. The dose of NSAIDs was reduced, and the patient has been observed for 4 months, with gradual recovery from anemia.

Nardilysin controls intestinal tumorigenesis through HDAC1/p53–dependent transcriptional regulation

Colon cancer is a complex disease affected by a combination of genetic and epigenetic factors. Here we demonstrate that nardilysin (N-arginine dibasic convertase; NRDC), a metalloendopeptidase of the M16 family, regulates intestinal tumorigenesis via its nuclear functions. NRDC is highly expressed in human colorectal cancers. Deletion of the Nrdc gene in ApcMin mice crucially suppressed intestinal tumor development. In ApcMin mice, epithelial cell-specific deletion of Nrdc recapitulated the tumor suppression observed in Nrdc-null mice. Moreover, epithelial cell-specific overexpression of Nrdc significantly enhanced tumor formation in ApcMin mice. Notably, epithelial NRDC controlled cell apoptosis in a gene dosage-dependent manner. In human colon cancer cells, nuclear NRDC directly associated with HDAC1, and controlled both acetylation and stabilization of p53, with alterations of p53 target apoptotic factors. These findings demonstrate that NRDC is critically involved in intestinal tumorigenesis through its epigenetic regulatory function, and targeting NRDC may lead to a novel prevention or therapeutic strategy against colon cancer.

Nardilysin inhibits pancreatitis and suppresses pancreatic ductal adenocarcinoma initiation in mice

Objective Nardilysin (NRDC), a zinc peptidase, exhibits multiple localisation-dependent functions including as an enhancer of ectodomain shedding in the extracellular space and a transcriptional coregulator in the nucleus. In this study, we investigated its functional role in exocrine pancreatic development, homeostasis and the formation of pancreatic ductal adenocarcinoma (PDA). Design We analysed Ptf1a-Cre; Nrdcflox/flox mice to investigate the impact of Nrdc deletion. Pancreatic acinar cells were isolated from Nrdcflox/flox mice and infected with adenovirus expressing Cre recombinase to examine the impact of Nrdc inactivation. Global gene expression in Nrdc-cKO pancreas was analysed compared with wild-type pancreas by microarray analysis. We also analysed Ptf1a-Cre; KrasG12D; Nrdcflox/flox mice to investigate the impact of Nrdc deletion in the context of oncogenic Kras. A total of 51 human samples of pancreatic intraepithelial lesions (PanIN) and PDA were examined by immunohistochemistry for NRDC. Results We found that pancreatic deletion of Nrdc leads to spontaneous chronic pancreatitis concomitant with acinar-to-ductal conversion, increased apoptosis and atrophic pancreas in mice. Acinar-to-ductal conversion was observed mainly through a non-cell autonomous mechanism, and the expression of several chemokines was significantly increased in Nrdc-null pancreatic acinar cells. Furthermore, pancreatic deletion of Nrdc dramatically accelerated KrasG12D -driven PanIN and subsequent PDA formation in mice. These data demonstrate a previously unappreciated anti-inflammatory and tumour suppressive functions of Nrdc in the pancreas in mice. Finally, absence of NRDC expression was observed in a subset of human PanIN and PDA. Conclusion Nrdc inhibits pancreatitis and suppresses PDA initiation in mice.

Utility of : A case report kras : A case report mutational analysis in the preoperative diagnosis of synchronous pancreatic cancer and intrahepatic cholangiocarcinoma: A case report

Rationale: It is often challenging to discriminate between intrahepatic cholangiocarcinoma (ICC) and metastatic liver tumors, especially when the hepatic tumor is small and of a mass-forming type. Patient concerns: We report a 69-year-old woman presented at our hospital with a small solid tumor in the head of the pancreas that was previously discovered during a medical checkup. Diagnoses: The patient was diagnosed with synchronous pancreatic cancer and ICC. Interventions: The patient underwent clinical, histological, immunohistological, and KRAS mutational analysis. Outcomes: Computed tomography revealed poorly enhanced small nodules in both the pancreatic head and liver. Biopsies of both nodules revealed adenocarcinoma; however, it was unclear whether the hepatic lesion was a metastasis of the pancreatic tumor or primary ICC. KRAS mutational analysis from FFPE biopsy samples revealed a discordance of mutation status between the tumors. Therefore, the patient was diagnosed with synchronous pancreatic cancer and ICC, whereupon she underwent hepatopancreatoduodenectomy. Lessons: KRAS mutational analysis of FFPE biopsy samples can be utilized for differentiating between ICC and metastatic liver tumor.